Hummingbirds

Many people enjoy watching hummingbirds. All across the US one can find hummingbird feeders in any neighborhood throughout the spring and summer. These tiny birds (which are only found in the western hemisphere) are not only fun to watch, they are fascinating creatures in how they have adapted to the challenges of life.

Throughout the eastern United States the most common hummingbird is the Ruby-throated Hummingbird. The mature males have a brilliant reddish/orange throat patch. These birds winter along the northern edge of South America. The most amazing part of this is that recent studies have found these tiny birds actually cross the Gulf of Mexico. In fact these amazing critters can carry enough fat to travel 1000km in 26 hours. This is more than enough to cross the Gulf unaided and travel several miles inland before stopping to refuel.

Ruby-throated Hummingbird

Another North American species that conducts extreme migrations is the Rufous Hummingbird. These birds are debatably the champions of long distance migration, migrating 3900 miles each way between Alaska and central Mexico. While they are by no means the champions in terms of distance they are certainly the champions in terms of body lengths. These birds travel over 78 million times their own body length, where as the Arctic Tern (the champion in terms of distance) only travels 51 million body lengths.

Rufous Hummingbird

As hummingbirds are a family of birds only found in the western hemisphere I would be remiss to not mention a South American species. Especially since South America has far more hummingbird species than than North America (compare ~150 species in Ecuador alone to only 18 species throughout all of North America, including the tropical climates of central American countries).

Probably the most impressive species from South America is the Ecuadorian Hillstar. These amazing little birds live at the highest elevations for any species of hummingbird. Found in the Andes Mountains of Ecuador, these birds live between 3,500 and 5,200 meters (11,500 to 17,100 feet) above sea level. These birds face great energy demands. Living at such high elevations nights can be freezing, and as hummingbirds they naturally have high metabolisms and body temperatures. If they were to maintain these body temperatures over night, when conditions are often freezing, they would quickly burn their energy stores. However, these birds have evolved to enter a state of torpor overnight in which they lower their core temperature to decrease the difference between their body temperature and the environment. This adaptation allows them to burn much less energy to keep their core body temperature steady. The next day they will increase their body temperature and metabolism and resume normal behavior. This amazing behavior has allowed them to thrive in an extreme environment.